Strains are tested for levels of various cannabinoids to help patients and budtenders know the strength and traits of the plant. This sample of Stevie Wonder is from Pure Medical Dispensary. (Joe Amon, Denver Post file)

A proposed ballot initiative and an amendment to a bill in the state House would cap the THC potency of recreational cannabis and marijuana products at a percentage below most of those products’ current averages.

The initiative would limit the potency of “marijuana and marijuana products” to 15 percent or 16 percent THC.

The average potency of Colorado pot products is already higher — 17.1 percent for cannabis flower and 62.1 percent for marijuana extracts, according to a state study.

Supporters of the legislation, introduced by Republican state Rep. Kathleen Conti, say they’re being cautious until more research has been done and protecting the brain development of adolescents. But opponents say the measures are unreasonable and could squash some of the legal cannabis industry’s most popular categories.

“All the studies that have been done on THC levels have been done on THC levels between 2 and 8 percent,” said Conti, whose district encompasses parts of Greenwood Village and Littleton. “Most of the marijuana coming in now, the flowers are being rated at a THC count of about 17 percent on average, so this is dramatically over, and we really don’t know that we’ve gotten the true feel on the health risks associated with that marijuana.”

The THC-limiting measures have the support of Smart Colorado, a group that focuses on Colorado youths amid cannabis commercialization.

“One of our legislative priorities for this year was to raise awareness of the high levels of THC in the marijuana products in our state,” said Henny Lasley of Smart Colorado. “Concentrates are of course what are put into marijuana edibles, and we have well over 300 of those food products, many many of which are attractive to children.

“And the high potency and unknown health impacts of those are deeply concerning to Smart.”

A portion of marijuana concentrate is removed for a dab during the 2014 Cannabis Cup at the Denver Mart. (Seth McConnell, Denver Post file)

Marijuana industry compliance professional Mark Slaugh considers the proposed THC limit “unconstitutional” and said such a cap would send patients and recreational users to the gray and black markets.

“I don’t think a lot of thought was put into the proposals,” said iComply CEO Slaugh, also the executive director of the Cannabis Business Alliance. “This bill threatens to wipe out most infused product manufacturers, and its language is unclear as to what to do with edibles.”

Josh Hindi, whose Dabble Extracts is a medical-only concentrates company looking to expand to the recreational side, said such a THC limit “would remove concentrates in total from any kind of retail operation.

“We would have to dilute our products to get them to 15 percent,” said Hindi, who estimates his extracts test between 70-80 percent THC and cater to patients who prefer the more potent product.

The first THC-capping proposal is a ballot initiative that would limit the potency of cannabis products to 16 percent THC, would require everything to be sold in a child-resistant, opaque, resealable package and would require edibles to be packaged and sold only in single-serving amounts. It would amend the state constitution and would apply only to retail marijuana, not medical.

The initiative — which was filed last week with support from proponents Ali Pruitt and former Lakewood High School principal Ron Castagna, who has previously spoken out against marijuana — would also define a single-serving amount as 10 milligrams of THC.

The initiative would also require all retail marijuana products to contain labels identifying the potency and providing warnings about “identified health risks,” including “birth defects and reduced brain development,” risks to the brain and behavioral development of babies, breathing difficulties, “permanent loss of abilities,” mood swings, impaired thinking and body movement, depression, temporary paranoia, anxiety, and “potential for long-term addiction.”

In order to qualify for the ballot, the proposed initiative must navigate a series of hearings, then proponents must collect 98,492 signatures from registered Colorado voters.

The second THC-limiting proposal is an amendment to HB 1261, a “sunset” bill that reauthorizes rules that are set to expire. Specifically, the bill would extend Colorado’s rules for the sale of retail marijuana until 2019, and would, among other things, eliminate a requirement that licensees post surety bonds and would create new “retail marijuana transport” and “retail marijuana operator” licenses.

The bill was heard by the House Finance Committee on March 24, and, after hearing from Smart Colorado’s Lasley, Joe Hodas of edibles brand Dixie Brands, Dean Heizer of retail cannabis giant LivWell Enlightened Health and others, the committee laid the bill over without taking a vote.

This amendment would ban recreational cannabis stores from selling “retail marijuana or retail marijuana products” with a THC potency higher than 15 percent. Knowingly violating the ban could result in a punishment as lenient as a license suspension and as strict as license revocation or a fine up to $100,000.

The amendment would also require a special label on marijuana or marijuana products containing more than 10 percent THC. The label would state: “Warning: The health impacts of marijuana with a THC potency of above 10 percent are unknown.” Lastly, the amendment would tighten up the suggested variance that stores would be allowed in potency measurements. Stores would have to be able to accurately report potency within plus or minus 5 percent.

According to the latest House calendar Monday, the bill has not yet been rescheduled for a vote in the Finance Committee.